This invention is concerned with conveyor belts of the type supported and driven by two rope circuits, each engaging the belt on the underside thereof at or adjacent a respective edge thereof.
Conveyor belts of this type must have considerable lateral stiffness to support the load carried, since the belt is supported only at its edges. However, in the longitudinal direction the belt must be flexible to permit it to be trained around guide drums. In a typical rope-driven conveyor for use in the mining industry, the span of the belt between the ropes is 36 to 41 inches and the carrying capacity requires a transverse stiffness which will satisfactorily deal with an E/I ratio (ratio of stress to moment of area) of about 2500 lb.in.sup.2. At the same time, in the longitudinal direction the belt must be sufficiently flexible to pass around end drums 12 inches in diameter, that is the belt must be capable of bending to a 6 inch radius.
In conveyor belts of this type hitherto used, the required transverse stiffness has been provided by moulding into the belt, which itself is made from flexible elastomeric or plastics material (hereinafter, for convenience, all referred to as "rubber," which is the preferred material for use in the present invention) laterally extending reinforcing members. Typically there has been used for this purpose spring steel strips each 0.2 inch in the direction of thickness of the belt and 0.5 inch longitudinally of the belt, the strips extending substantially across the whole width of the belt and being spaced at intervals of 3 inches along the belt.
Such a construction is expensive in both materials and fabrication costs.